This invention relates to surgical fasteners, and more particularly to a retainer member assembly for facilitating application of such surgical fasteners to body tissue.
Surgical stapling devices allow a surgeon to fasten body tissue by applying surgical staples. The staples may be applied singly in succession or a number may be applied simultaneously. Surgical staples are often made of metals such as tantalum or stainless steel, which are inert. Fasteners of magnesium, which fasteners are gradually absorbed by the body, are also known.
Non-metallic fasteners are also known and in some cases may have certain advantages over metal staples. For example, metal staples in the body may scatter X-rays and may therefore degrade the quality of radiographs.
However, metal staples also have certain advantages over non-metallic fasteners. They can be bent or crimped and will hold their new shape in or around tissue. In contrast, objects of non-metallic resinous materials are usually too resilient (i.e., elastic) to hold deformed shapes (assuming plastic flow does not occur). (As used herein, the term "resinous materials" means non-metallic materials, such as natural or synthetic polymers and resins, including protein-based materials, which are relatively flexible and elastic, and which may or may not be absorbable in the body.)
To circumvent this characteristic of resinous materials, surgical fasteners of these materials may be made in two parts: a fastener member and a retainer member. The prong or prongs of the fastener member are driven through one side of the tissue to be fastened and the retainer member interlocks with the prongs of the fastener member on the other side of the tissue to hold the entire fastener structure in place. One such fastener structure and apparatus for applying it are disclosed in Green U.S. Pat. No. 4,402,445 issued Sept. 6, 1983, which is hereby incorporated by reference in its entirety.
Such fastener structures are relatively small in size and typically are applied to tissue several at a time in rows. Because of their small size, loading the fastener and retainer members into the fastener-applying apparatus can be both tedious and time-consuming. The need exists for fastener structures that can be loaded quickly and easily.